I know this link is for Ubuntu 5.10, but it worked in 6.06 for my 17'' CRT. Now Ubuntu recognizes all the resolutions and refresh rates that my monitor can handle.
http://www.ubuntuforums.org/showthread.php?t=83973
Scroll down to ''How to reconfigure Xorg.'' I do the whole X configuration process. Make sure that the correct video card family is selected. Enter your horizontal and vertical refresh rates manually (find them in your monitor's manual). If you are not sure about certain settings, use the defaults.
Hope this helps.
i recently installed this on a spare harddrive...everything was going fine..i liked it..but then it said i had updates ready to download/install so i did...(i do not know for sure what they were sorry) now i cannot get higher than 640x480 resolution.. please help

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